Today’s inspection on a 1990 townhome revealed two electric 40-gal water heaters that were sort of hooked up in series. However, I’ve never seen a connection like this. Unit #1 feeds Unit #2, however it feeds into Unit #2 at the drain valve. The Unit #1 drain valve has a pipe that feeds over to a E-Tech Heat Recovery Unit. What would normally be the cold water input on Unit #2 also feeds over to the E-Tech Heat Recovery Unit.
I presume E-Tech is similar to a hot water circulating system, but I’m not totally sure. A lot of what I read had it working in conjunction with a heat pump. While there was a heat pump present at the townhome, there were no lines from the E-Tech or water heaters to the air handler.
I’ve also never seen where a series connection would go into a drain line, or where a drain line was used for something other than draining. I was wondering if anyone else has seen anything like this. Any input would be appreciated.
I can’t help you a lot, but I am familiar with geothermal hydronic heat buffer tanks that utilize the tank base nipple. The reason is to maintain heat stratification within the buffer tank. It adds to heating system efficiency.
You say this is a “parallel water heater setup”. Is it connected to the domestic water supply system? If it’s a domestic water heater and not a buffer tank, I’m out of my league. Someone else will have to carry on from here.
As with Michael, I do not think I can help that much without further explanation.
Lets start with, what was conditioned through hydronics in the residence?
I do not think the water heaters are plumbed in series. Maybe tandem.
Looks like a setup for some kind of hydronic heating arrangement. Perhaps radiant flooring?
The right tank appears to be storage only as it is not wired. Electric tank units have poor recovery times. How large is the house? How far does the hot water have to travel?
A common misconception of tankless units is that the hot water is “instantly” available. The water still has to traverse all the pipe to the faucet.
I agree, it’s plumbed like a buffer tank. However, he said it’s a “parallel water heater”. The OP hasn’t clarified whether this “water heater” is connected to the domestic water supply system or connected to a hydronic heating system.
My curiosity is piqued…waiting for the OP to reply.
Hey Bob, I noticed the second tank wasn’t wired, which also didn’t make sense to me. Why would you use your first tank for storage? It’s a two-story, 1600 sq ft, townhouse with a basement. The water heaters were in the basement.
The water pressure was high (140 PSI when measured on the farthest hose bib from the street shutoff). All the faucets had strong flow.
Hey Brian, I checked the unit and there was no power supplied. It appeared to be not working and there were no sounds of water flow through the unit. I also saw the cut copper lines. The two lines that feed are on the lower right corner of the photo.
I have seen these recovery units but they are rare in my area (GA), always non-operational and at least 2 decades old. In your case, it has become a liability with signs of leaking and corrosion. I know this was not your question, but I just recommend removal of the obsolete equipment.
Researching on the ole Interweb, E-Tech is still in business, but seems to be more on the commercial side now making economizers for boiler systems and perhaps not in the residential market anymore. This was likely a heat recovery system that used waste heat from an HVAC condenser or refrigeration unit to preheat water to the water heater, making it more efficient. The box likely contains a heat exchanger and a small recirculating pump to move the potable water through the heat exchanger and water heaters. But, as already discovered, the connections to the heat source seem to have been cut and the pump is no longer powered. So, now all it is is a heat sink (wasting energy) and is liable to leak. If it were me, I would recommend it be removed.
